1. Field of the Invention
This invention relates to an automatic dispenser for a plurality of liquids. More specifically, the invention relates to an automatic computer controlled liquid colorant dispenser.
2. Description of the Prior Art
Since 1966 when the State of California passed Rule 66 which regulates solvent discharge into the air, many Federal and State environmental laws, including the recent Clean Air Act of 1990, have followed. These laws are changing the way we make, package, distribute, apply, and dispose of architectural paints, which are the most polluting consumer product after automobiles. For instance, one gallon of solvent (oil) based paint discharges more hydrocarbons into the air than a Cadillac discharges in nine months of driving. Therefore, use of solvent based paint is already banned in many areas in this country. Although the alternative water-borne latex paints cause less air pollution, they cause severe water pollution. Disposal of left-over paints, empty cans, and discarded applicators, as well as waste water or solvents from cleaning manufacturing equipment in factories and tools at job sites add more air, water and solid pollution.
In anticipation of ever tightening regulatory pressure on the paint industry, we have been developing a virtually non-polluting alternative technology, known as the EcoPainting System, for the last two decades. This system reduces the total pollutants to about one thousandth of those caused by conventional ways of making, packaging, applying and disposing of architectural paints. Many components of this system have been patented and are in the market.
This invention, named ACCEPT (Automatic Computer-Controlled EcoPaint Tinter), is the latest component of the EcoBatch paint making process, which is designed to produce an exact amount of paint of any gloss or color from four pre-dispersed ingredients in retail stores without creating any waste product. The EcoBatch process consists of computer controlled base making, tinting, and color matching, and EcoPackaging which is described in the U.S. Pat. Nos. 4,898,295, 4,977,724, and 5,016,755. We have separated the tinting machine portion of the EcoBatch paint maker from other parts and modified it for conventional paint retail store use.
In paint retail, four major new developments are helping the rapid growth of custom tinting and automation. A decade ago, standard packaged colors were the major portion of trade paint sales but presently they contribute to less than half. Firstly, the ever tightening governmental regulations are raising the cost of waste treatment. This regulatory and economic pressure forces the paint manufacturers to reduce the number of products or smaller batches to reduce cleaning and the resulting hazardous wastes. Secondly, the sophisticated tastes of baby boomers demand more variation than the usual twenty or so standard colors can provide. Thirdly recent advances in personal computers (PC) make PC-based store automation affordable to even a mom-and-pop store. Finally, the new emergence of low cost spectrophotometers and the color matching software are making custom tinting faster, easier and more affordable.
In a conventional custom tinting, a customer select a color from a sample color book or color chips, which tint manufacturer supplies with their tints as a part of their color system, such as the ColorTrend System by Nuodex Corporation. Using the number from that color chip, a clerk searches and copies the corresponding formula from a formula book which the paint manufacturer supply with tint bases. He dispenses the proper amounts of each tint into a can of base paint by setting metering pumps one at a time. After mixing the contents by shaking, he visually checks the color, then gives it to the customer. This process is time consuming, labor intensive, and prone to human errors in each step. An average tinting takes more than 15 minutes and about five percent of custom tinted paints are mis-tinted and wasted. Obviously, these wastes can be reduced by replacing the human operator with an automatic tinter using electronically stored formula. Spectrophotometer based color matching already involves the use of a computer, allowing easy interfacing with an automatic tinter.
To fill these needs, five U.S. and one foreign manufacturers have introduced automatic tinters during the last several years. These units are generally designed for factory use. They are large, about the size of an office desk, and costly, over ten thousand dollars. Two of these are merely motorized hand tinters. These units dispensing one tint at a time, and are very slow. The most popular ACCUTINTER by Miller Manufacturing Company of Wheeling, Ill. has a set of metering gear pumps. Abrasion by pigments tends to wear the gears and causes loss of metering precision. This unit is very expensive, costing over twenty thousand dollars and also is expensive to maintain because a skilled repairman must come to the store. Also this unit has its own separate central processing unit (CPU), memory, keyboard, and screen, a complete but limited capability computer. This is unnecessary duplication, resulting in additional cost and service needs. It is more practical and economical to shift all control functions, except the minimal safety over-rides, to a more readily available general purpose PC. This arrangement can simplify all interfacing with other retail automation software which is written for PCs.
The accuracy of presently available tinters is in the order of one-sixty-fourth of an ounce mainly because they are designed for tinting a large volume of paint, such as five-gallon pails. This is totally unsuitable for most retail store operations, where quart cans and light pastel colors are a significant portion of their tinting business. In practice, one can tint only a full gallon of pastel color paint since the tinters are not capable of dispensing a smaller amount of tint accurately. The left-over is wasted and becomes a pollutant. For the EcoBatch process, the tinter must be capable of dispensing about one-four-hundredth of an ounce of tint accurately to tint one pint of paint in very light pastel colors and, at the same time, be compact enough to fit into the counter-top space which a hand tinter occupies now. Being unable to find any commercially available tinter which can meet the above strict requirements, the following invention had to be made.